Decided to run some math to see just how effective my Gloom Prisms are, and I figured I would share it here for anyone to use. These chances I am listing are for both the power successfully casting (at various leadership values) and getting through different forms of Deny the Witch and such.

Bleh, took me longer to figure out how to format this in a readable manner than it did to crunch the math. While the Gloom Prism isn't quite up there with the Tau Amulet, it certainly makes any of my squads hugging a Spyder feel safer.